Tape libraries have historically been the primary storage devices for amassed digital data. This has been due in part because of the tape libraries' ability to store considerably large amounts of data in a cost-efficient and data-stable manner. Other types of storage systems containing alternative media such as disc drives, however, are beginning to gain momentum as a consequence of advancements in the technology. Disc drive-based systems generally facilitate an additional level of flexibility in the way data is stored. Depending on the configuration of the storage system, the random access functionality of disc drives can dramatically speed up data transfer between a host and storage system. Such advances are evident in a Virtual Tape Library (VTL) which is a leading alternative to the traditional tape library.
VTLs are generally promoted as faster, more versatile backup systems than the traditional tape-based libraries. A VTL works by emulating legacy tape libraries by operating with standard tape backup software, such as Veritas backup software from Veritas Corporation of Mountain View, Calif. Put simply, a VTL presents the appearance of a tape library of almost any make and model to a host. Hence, data can be transmitted to a VTL in streaming protocol whereby data can be stored on media as a contiguous data packet emulating the linear last-in/last-stored format of tape media.
One limitation inherent in all recording media includes limited storage capacity. This is generally addressed by replenishing space for new data storage with compression techniques or simple data deletion. When such practices are employed with data stored in a streaming protocol on tape media, certain restrictions exist. For example, data stored sequentially on tape media in a relative order of first-in/first-stored to last-in/last-stored are deleted contiguously to include data last-stored. This methodology is followed because the data stored on tape is generally contiguous from file to file due to the linear nature of tape media. Thus, having gaps of useable space from intermittent deleted files in the data stream would most likely create complex data management challenges to store new data in streaming protocol on the useable space.
The invention described herein is, therefore, generally directed to leveraging the benefits of non-tape media for use by systems and software that typically are specialized to work with tape media.